1. Field of the Invention
This invention relates to a deer antler extract. In particular, the present invention relates to angiogenic extracts obtained from deer antler velvet, and compositions containing said extracts for use in the treatment of wounds, injuries and diseases in human and animal medical practice.
2. Description of the Related Art
Wounds, in particular persistent wounds, which are difficult to heal, require a blood supply that can nourish the wound and mediate the healing process and minimize scar formation. Generally, most commonly used therapies for treating persistent wounds do not assist the wound to provide its own blood supply and therefore the healing process is slow.
Various therapies for the treatment of chronic wounds exist, however, the use of compression bandages still appears to be a common treatment (Marshall et al., 2001). Other therapies are available and some natural therapies have been proposed that work through mechanisms involving regulation of oxygen tension, and thus support hyperbaric oxygen treatments (Sen et al., 2002).
The healing of wounds by increasing angiogenesis (the process of vascularisation of tissues) is apparent with some proposed therapies. In a recent study adenosine appears to have increased the rate at which wounds healed by acting as an adenosine A(2A) receptor agonist (Montesinos et al., 2002). This resulted in increased numbers of micro vessels in the treated wounds. Increased angiogenesis is a likely mechanism underlining the improved healing shown in this paper.
The well known classical angiogenic growth factor Vascular Endothelial Growth Factor (VEGF) has been shown to cause angiogenesis and enhanced wound healing, when delivered by gene therapy to ensure local sustained delivery (Deodato et al., 2002). Malinda et al. (1998) have found that Thymosin α1 stimulates endothelial cell migration, angiogenesis, and wound healing, also confirming it as a potential wound healing agent.
Deer antlers are cast and regenerate annually. The antler grows at up to 2 cm a day during its growth phase, during which time it is termed ‘velvet antler’. The growth is driven by a population of stem cells found in mesenchymal tissue at the tip of the antler (Li et al., 2002). Velvet antler is highly vascularised and blood vessels within the antler must grow at the same rate as the antler to support antler growth. We have identified this system as a potential source of angiogenic factors that will support wound healing processes.
There is one paper that suggests that the healing or regenerating pedicle, which they called the blastema, may have angiogenic potential (Auerbach et al., 1976). This paper involved the author screening a variety of tissues including antler blastema with the aim of showing that some tissues contained angiogenic potential. Importantly however, this paper did not contain any data showing actual angiogenic or wound healing activity. Blastema referred to the healing tissue which appears once the antler has cast, and is different from the more mature growing antler which the inventors have studied and outline in this specification.
There are no published reports of growing deer velvet antler being investigated in relation to its angiogenic effects. The inventors have found that total protein extracts of growing velvet do contain angiogenic factors.
The research outlined in this specification shows that extracts of deer velvet which contain these angiogenic factors are extracted from throughout the antler and are not just concentrated within the growing antler tip.
The inventors have prepared a composition of isolated peptides extracted from deer velvet antler which has an angiogenic effect and can be used to heal wounds.
The inventors fractionated velvet to assess the angiogenic potential. As part of the fractionation process they investigated high and low molecular weight fractions of velvet, and were surprised to find that the low molecular weight fraction had good activity. This was an encouraging result as smaller molecules are more likely to be stable and not degrade so rapidly within a wound.
Based on their molecular weights, most classical angiogenic growth factors would be expected to be found in the high molecular weight fraction, one exception to this rule would be the Thymosin family of peptides.
All references, including any patents or patent applications cited in this specification are hereby incorporated by reference. No admission is made that any reference constitutes prior art. The discussion of the references states what their authors assert, and the applicants reserve the right to challenge the accuracy and pertinence of the cited documents. It will be clearly understood that, although a number of prior art publications are referred to herein, this reference does not constitute an admission that any of these documents form part of the common general knowledge in the art, in New Zealand or in any other country.
It is acknowledged that the term ‘comprise’ may, under varying jurisdictions, be attributed with either an exclusive or an inclusive meaning. For the purpose of this specification, and unless otherwise noted, the term ‘comprise’ shall have an inclusive meaning—i.e. that it will be taken to mean an inclusion of not only the listed components it directly references, but also other non-specified components or elements. This rationale will also be used when the term ‘comprised’ or ‘comprising’ is used in relation to one or more steps in a method or process.
It is an object of the present invention to address the foregoing problems or at least to provide the public with a useful choice.
Further aspects and advantages of the present invention will become apparent from the ensuing description which is given by way of example only.